The present invention relates to a dispenser, particularly though not exclusively for dispensing aerosol or powder borne medicaments.
As used herein, xe2x80x9ckinkingxe2x80x9d in respect of a tube means bending the tube to such extent that it collapses on itself, closing its internal passage.
It is well known to administer medicines, for instance for asthma, from a dispenser adapted to provide a metered dose under gas pressure. For satisfactory administration, the patient should inhale the medicine into his/her lungs. This is eased if the dispensing is in phase with the patient""s inhalation. Various dispensers exist which are actuated by the act of inhalation.
A difficulty with breath actuated dispensing is that the force available from the act of inhalation is very small, which renders simple, reliable actuation difficult. Generally the dispenser is cocked by the Application of a much greater force than can be achieved by inhalation, and the inhalation force is used to release the dose. This calls for a mechanism with several parts.
In my earlier patent U.S. Pat. No. 2,233,236, I described an aerosol medicament dispensing device in which a metered dose is received into a storage chamber and released therefrom by a breath actuated valve.
Further in another earlier application No. PCT/GB91/02118xe2x80x94WO 92/09323, I have proposed another aerosol medicament dispensing device in which a preload for dispensing from the aerosol is applied and resisted by pneumatic force. The pneumatic force is released by a breath actuated valve.
The object of my present invention is to provide a simpler alternative to my earlier dispensers, by providing a simple breath actuatable valve which can be incorporated therein.
According to the invention there is provided a valve comprising:
a valve inlet,
a valve outlet,
a flexible tube extending between the inlet and the outlet, the tube having a movable portion which is movable between closed position in which the tube is kinked for closure of the valve and an open position in which the tube is un-kinked for opening of the valve and
a movable member for moving the movable portion of the tube to control the kinking of the tube.
Whilst in some embodiments the unkinking of tube will involve at least partial straightening of it, it should be noted that the flexible tube will in most cases allow flow whilst still curved but not kinked.
The tube itself may be a length of plastics material tube. Preferably it is permanently shaped to predetermine the position of the obturating kink(s).
In certain embodiments, the tube has a single kink when the movable member and the movable portion of the tube are in their closed position, the tube then preferably having a V or L configuration. In other embodiments, the tube has a pair of kinks when closed, the tube then preferably having a Y, M or Z configuration.
The movable portion of the tube can be an end portion of the tube, connected to or providing the inlet or the outlet of the valve, in which case the end portion of the tube can be movable axially to kink and un-kink the tube, i.e. to close and open the valve, or the end portion of the tube car be movable angularly to kink and un-kink the tube.
Alternatively the movable portion of the tube can be a middle portion of the tube, between end portions connected to or providing the inlet and the outlet of the valve.
Whilst it can be envisaged that the valve will be a normally open valve, usually it will be normally closed, a spring being provided to urge the movable member to its closed position.
In particularly preferred embodiments, the valve is breath actuatable, the movable member being a vane movable by inhalation or exhalation. The vane can be a piston or a pivoted flap.
Thus the invention also provides a dispenser for a gaseous, gas borne or droplet substance, the dispenser including a valve of the invention, and further comprising:
a body including a mouthpiece with an inhalation/insufflation orifice at its end and
a junction for a source of gas or evaporable liquid comprising or containing the said substance,
and wherein:
the vane is movably mounted in the body for movement by the act of inhalation from a rest position towards the orificexe2x80x94or at least in the direction of air flow through the dispenserxe2x80x94and
the valve is connected to the junction for controlling the said gas or liquid with the valve inlet being at the junction, the flexible tube extending from the junction for receiving the said gas or liquid and connected at the outlet end to the breath actuatable vane for movement therewith, the tube being kinked to an obturating extent when the vane is in its rest position and un-kinked when the vane is moved on inhalation for release of the gas or liquid.
Whilst it is envisaged that the vane may be a diaphragm or pivoted flap, in the preferred embodiments, the vane is a piston. The vane may be inherently resilient for biasing to the rest position or may be urged there by gravity; however in the preferred embodiments, a spring is included to urge the piston to the rest position.
Preferably, the vane is a piston slidably mounted in a bore in the body at or adjacent the mouthpiece. Usually, the body and/or the piston will be provided with an air bypass to enable air to be inhaled to bypass the piston when it has moved the tube to its un-kinked, open position. The bypass can be a series of notches in a skirt of the piston and an enlargement in the bore, the bypass opening when the notches move into register with the enlargement.
In accordance with another feature, the piston is provided with a manually actuatable member extending through a wall of its bore and the piston and its bore are provided with a notch and detent mechanism for holding the piston in either or both of its open and closed positions, whereby the piston can be manually moved to and held in its position holding the tube in its kinked, closed and/or to its un-kinked open position by engagement of the notch and detent mechanism. Alternatively, a manually actuatable member may be provided merely for holding the piston in its open position with the tube un-kinked and open for purging discharge from the said source.
Where a spring is provided for normally closing the valve, it can be a compression spring biasing the piston inwardly of the mouthpiece, the spring acting between the piston and an abutment in the body. Alternatively, the spring can be a tension spring biasing the piston inwardly of the mouthpiece, the piston and a formation in the body being adapted to connect to the spring for its biasing of the piston.
In one embodiment, a dispenser is provided for use with a source of the substance in pressurised gaseous or liquid form of the type which releases a dose on depression of an outlet tube of the source, wherein:
the body is generally L-shaped,
one limb of the L is a sleeve for accommodating the source of gas or evaporable liquid,
the other limb terminates as the mouthpiece,
a block:
is provided integrally with and internally of the body in line with the one limb,
has a socket for receiving an outlet tube of the source and
is the junction to the valve with the socket in communication with the valve tube, and
the piston is the outlet from the valve and has the valve tube in communication with a throughbore in the piston,
the arrangement being such that depression of the source in the one limb releases a dose of the said substance into the valve tube for release on valve opening by inhalation.
In this embodiment, the block preferably has a lateral communication with the valve tube and the latter has a Z configuration when kinked and closed.
In another embodiment, a dispenser is provided for use with a source of the substance in pressurised gaseous or liquid form of the type which releases a dose on depression of an outlet tube of the source, wherein:
the body is generally L-shaped,
one limb of the L is a sleeve for accommodating and captivating the source of gas or evaporable liquid,
the other limb terminates as the mouthpiece,
a block:
is provided movably in the body in line with the one limb,
has a socket for receiving an outlet tube of the source inside the body and an actuation button outside the body and
is the junction to the valve with the socket in communication with the valve tube, and
the piston is the outlet from the valve and has the valve tube in communication with a throughbore in the piston,
the arrangement being such that depression of the button towards the body releases a dose of the said substance into the valve tube for release on valve opening by inhalation.
In this embodiment, the block preferably has an axial communication with the valve tube and the latter has an L configuration when kinked and closed.
In yet another embodiment, a dispenser is provided for a gaseous, gas borne or droplet substance, the dispenser including a valve of the invention and further comprising:
a body including a mouthpiece with an inhalation/insufflation orifice at its distal end,
a source of the substance in pressurised gaseous or liquid form of the type having a container and a depressable outlet tube which releases a dose on depression towards the container and
depression means for releasing a dose, the depression means including:
a depression spring arranged to act on the source for releasing a dose,
a pneumatic actuator for resisting the action of the spring when a chamber of the actuator is closed,
a port opening into the chamber,
means for compressing the spring to cock the dispenser and
non-return means for allowing air to escape from the chamber as it is compressed for cocking,
and wherein:
the vane is movably mounted in the body for movement from a rest position towards the orifice by the act of inhalation and
the valve is arranged for controlling the port into the chamber, the port being the outlet from the valve, the flexible tube being secured at its inlet end to the breath actuatable vane for movement therewith, the tube being kinked to an obturating extent when the vane is in its rest position and unkinked when the vane is moved towards the orifice on inhalation for release of the contents of the container by allowing air to enter the chamber and the spring to act to release the dose.
In this embodiment, the vane is preferably a flap pivotably mounted in the body and the spring is a torsion spring acting about the pivot of the flap in body.
Whilst the dispensers may find use for continuous dispensing, normally they will be used for dispensing metered doses. These may be released by the source of gas or liquid in measured doses. However it is envisaged that the source may be arranged to release into a space at least partially limited by an obturating kink to measure the dose.